Structure-function relationships in cellular copper control
Date
2009
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Degree Level
Doctoral
Abstract
X-ray absorption spectroscopy and computational chemistry have been used to probe the structure of biomolecules involved in cellular copper homeostasis. X-ray absorption spectroscopy shows that copper chaperones involved in cytochrome c oxidase assembly bind Cu(I) with trigonal coordination environments in poly-copper thiolate clusters, but the number of coppers in these clusters remains unclear. X-ray absorption spectroscopy of the metal-sensing transcription factor-1 from Drosophila melanogaster and metallothionein from Saccharomyces cerevisiae with stoichiometries of four or less shows a tetracopper cluster in an all-or-none manner in these molecules. These results suggest that cooperative binding of copper to form tetracopper clusters may be a common mechanism employed by copper control molecules. The active site structure of the novel copper-sensitive repressor CsoR in Mycobacterium tuberculosis binds copper in a trigonal coordination geometry with two sulfur and one nitrogen donors according to X-ray absorption spectroscopy results. Molecular dynamics simulations of both apo- and Cu-bound CsoR reveal local conformational changes in CsoR upon copper binding, which suggests multiple possible mechanisms of Cu-dependent transcriptional regulation by CsoR. Finally, X-ray absorption spectroscopy and X-ray fluorescence imaging have been used to understand the molecular basis of a promisng new treatment for Wilson’s disease (a genetic disorder of Cu homeostasis) using tetrathiomolybdate. Overall, the results presented provide an essential structural basis for understanding copper homeostasis in living cells.
Description
Keywords
density functional theory, X-ray absorption spectroscopy, cellular Cu control, molecular dynamics, metallothionein, Cu chapterone, CsoR, MTF-1
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Geological Sciences
Program
Geological Sciences